日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

Recent applications of XPS techniques to zeolites are reviewed to show characteristics of external and inner pore surfaces. The surface composition of zeolite is dependent on a synthesis method and particle size and strongly modified by dealumination procedures and surface modifications. XPS provides important information on the electronic structure and chemical bondings of zeolites. It is reported that the O1s binding energy decreases, that is, the electron density of framework oxygen increases with the increase in the Al-content or with the decrease in the electronegativity of the extraframework cation. Bonding models of zeolites proposed in literature are critically reviewed. The basicity of zeolite can be evaluated by an XPS study of pyrrol adsorption. The framework oxygens adjacent to the cation are proposed to be strongly basic. The acidic nature is characterized by pyridine adsorption. The N1s binding energy depends on acid form (L or B) and acid strength. Catalytic properties of zeolite are briefly discussed on the basis of the XPS characterization.